Closely examining the capillaries of the fingers, perhaps one of the most non-invasive procedures possible, may be provide insight into pulmonary function in patients with systemic sclerosis (SSc). A research group from Spain, led by Drs. Ivan Castellvi and Jordi Casademont, identified worse forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (DLCO) in SSc patients who had capillary density loss.
The team utilized a technique known as nalifold videocapillaroscopy (NVC), which involves analyzing the capillary bed of a patient’s fingers at high magnification. NVC has been used to determine disease-related microvascular changes and plays a role in diagnosing SSc. According to reports from Arthritis Research & Therapy and The Journal of Rheumatology, certain patterns visible with NVC can indicate patient prognosis and disease severity.
In the study, entitled, “Association Between Nailfold Capillaroscopy Findings and Pulmonary Function Tests in Patients with Systemic Sclerosis,” the authors conducted a retrospective study of patients from Barcelona, Spain, who had received both a pulmonary function test and at least one NVC in the same year. FVC, DLCO, and FVC/DLCO ratio were collected for 85 patients who qualified to be in the cohort. Similar to previous findings, there was a greater percentage of women with SSc who were identified, and limited cutaneous SSc was more common than diffuse cutaneous SSc.
Most interesting to the authors was the relationship between pulmonary function tests and NVC. Patients with notable capillaroscopic findings, such as giant capillaries or angiogenesis, had worse, but insignificantly different, FVC and DLCO values than patients without. When capillary density was considered, patients with capillary density loss had worse FVC and DLCO values. FVC/DLCO ratio was not associated with the different capillaroscopic findings.
“Ours is the first study, to our knowledge, that finds an association between capillaroscopic alterations and impaired lung function,” wrote the authors. “Patients with SSc and less capillary density had lower FVC and DLCO values, which therefore led to worse lung function.”
With these results in mind, NVC may hold more utility than previously thought in making diagnoses and prognoses for SSc patients. As NVC is already considered useful for identifying disease markers, future studies determining if NVC can monitor pulmonary function may be pursued further.